Table 6. Occupancy patterns of male Bobolinks and male Savannah Sparrows between visits based on changes in field conditions on agricultural fields in the Champlain Valley of Vermont and New York, May 21 to July 2, 2002. Each heading reflects a possible mowing history between successive sampling visits: never mowed (uncut-uncut), mowed between visits (uncut-cut) or allowed to regrow following earlier mowing (cut-regrowth). Counts reflect number of fields. Each field in the study is represented twice because each field had two opportunities to undergo change in mowing (i.e., between visits 1 and 2 and between visits 2 and 3).

Field condition Bobolink Savannah Sparrow
Uncut-uncut
Never recorded 77 97
Always recorded 87 53
Local colonization 12 19
Local extinction 21 28
Uncut-cut  
Never recorded 20 14
Always recorded 6 20
Local colonization 1 11
Local extinction 20 2
Cut-regrowth  
Never recorded 23 4
Always recorded 2 20
Local colonization 1 3
Local extinction 3 2